A cone crusher may be utilized for efficient crushing of material, such as stone, ore, etc. An example of a cone crusher can be found in EP 2 116 307 disclosing a cone crusher of the inertia cone crusher type. Material to be crushed is fed from a feeding hopper into a crushing chamber formed between an outer crushing shell, which is mounted in a frame, and an inner crushing shell, which is mounted on a crushing head. The crushing head is mounted on a crushing head shaft. In an inertia cone crusher an unbalance weight is arranged on a cylindrical sleeve-shaped unbalance bushing encircling the crushing head shaft. The cylindrical sleeve is, via a drive shaft, connected to a pulley. A motor is operative for rotating the pulley and, hence, the cylindrical sleeve. Such rotation causes the unbalance weight to rotate and to swing to the side, causing the crushing shaft, the crushing head, and the inner crushing shell to gyrate and to crush material in the crushing chamber. If the crushing chamber is emptied of material there is a certain risk that the inner crushing shell may get into contact with the outer crushing shell, resulting in wear.